simple-login/app/templates/_formhelpers.html

{% macro render_field(field) %}
  <div class="form-group row">
    <label class="col-sm-2 col-form-label">{{ field.label }}</label>
    <div class="col-sm-10">
      {{ field(**kwargs) |safe }}
      <small class="form-text text-muted">{{ field.description }}</small>
      {% if field.errors %}

        <ul class="errors">
          {% for error in field.errors %}<li>{{ error }}</li>{% endfor %}
        </ul>
      {% endif %}
    </div>
  </div>
{% endmacro %}
{% macro render_field_errors(field) %}
  {% if field.errors %}

    <ul class="errors">
      {% for error in field.errors %}<li class="text-danger">{{ error }}</li>{% endfor %}
    </ul>
  {% endif %}
{% endmacro %}